Ключевые слова: background, black, chert, close, cobble, collection, crystal, crystalline, edge, flint, gem, gemmological, gemmology, gemology, geological, geology, gray, isolated, little, macro, material, mineral, mineralogy, natural, nature, nobody, object, obsidian, ore, pebble, piece, quartz, raw, reflection, rock, sample, sedimentary, sharp, shiny, shooting, single, small, specimen, stone, structure, surface, texture, textured, up, white,